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<h1 style="text-align: center;">Velocityme Technology Components</h1>
<h2>Front end web server - Apache</h2>
Apache is the industry standard web server application. It runs under
Linux and is responsible for delivering the vast majority of content to
the world wide web.<br>
<br>
We are using Apache to manage the secure connection from the client's
web browser. Internally, it will pass any requests for the velocityme
site to the back end JSP server which is actually responsible for
creating and formatting the web pages.<br>
<br>
<h2>Back end JSP (Java Server Pages) server - Tomcat</h2>
Tomcat is a JSP web server written entirely in Java. JSP (Java Server
Pages) is an alternative to PHP based on the Java language. While
Tomcat is capable of being the front end web server, there are two
reasons why this is not usually the case:<br>
<ol>
  <li>It is not as fast as Apache for delivering normal web content
(Apache does not support JSP itself) and so a site will almost always
already have an Apache server.</li>
  <li>It is not as easy to make secure as Apache. Effectively, we are
going to use Apache as a firewall to hide our Tomcat server behind.</li>
</ol>
We use Tomcat to interact with the client browser. It therefore has to
create web pages to deliver to the client as well as respond to any
actions which the client performs. The is achieved using technology
called JSP. Internally, the JSP pages use Session Beans to interact
securely with the Velocityme application running in the JBoss
application server.<br>
<br>
<h2>Application server - JBoss</h2>
JBoss is a very popular J2EE application server written entirely in
Java. Because it is written in Java it can be run on different
architecture server computers. JBoss is responsible for providing a
container in which our Velocityme application is run. It manages the
connections between Velocityme and Tomcat and the database.<br>
<br>
<h2>Database - PostgreSQL</h2>
PostgreSQL is highly scalable, SQL compliant, open source
object-relational database management system. It is used to store all
the information that is entered into the Velocityme system.<br>
<br>
<h2>Application - Velocityme</h2>
Velocityme is a J2EE application written using Enterprise Java Beans
(EJB). It consists of various levels which are described below:<br>
<ol>
  <li>Entity beans are used to represent persistent information that is
stored in the database.</li>
  <li>Session beans encode the business logic of the application, what
the user is allowed to do.</li>
  <li>JSP and taglibs interact with the session beans to interface with
the web client</li>
  <li>CSS (Cascading Style Sheets) are used on the web client to define
the presentation of the data.<br>
  </li>
</ol>
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